I am planning on installing Solaris 11.1 as this will provide me with some storage to play at home with zfs while learning Solaris 11.1 at home and getting familiar with it more and more.

I have used Solaris before and have used Opensolaris as well.

Now the question is :

a) I have read for non-commercial use Solaris is free ? is this true ?
b) I know it is a free download, if I install, will I be able to get updates like other linux distros (I know this is not linux) frequently ?
c) What will you recommend instead of Solaris - or this is ok ?
d) Any thoughts on the hardware ? Compatibility ? Any graphics card should work or is solaris very specific ? I have 2 Nvidia Quadro cards lying around as spares as well.

The download page on OTN provides access to the license terms. I'd suggest you read them for yourself and decide how they apply to your planned usage.

Access to the support repositories requires a support contract.

Regarding support of specific hardware, the compatibility list on OTN may prove helpful. The best answer is to download the live CD and boot it; the device driver utility can be used to scan your hardware and report on driver support.

Obviously Oracle Linux is a consideration.
... If I went into 'sales' mode I'd say:
- Great new filesystems btrfs and zfs available to raid your storage. NOTE ( I thought I understood zfs was available on oracle linux .... but I've never tried it) ... now not so sure
- Support available, including through ULN (Unbreakable unix network).
- Ability to run solaris 11 (and other stuff) through virtualbox contained (possbile performance degradation).

That said I'd trust Solaris zfs before the two above. And I'd leave you to work out what people are saying about the downsides. Having said that I'd say Oracle are very keen to say their btrfs nd zfs implementations are good. Even ext4 with the raid manager and volume manager is quite capable. And solaris 11 also has virtualbox. Obviousl anything detailed on Oracle Linux on the Oracle Linux forum.

My understanding (possiblly imperfect) is For peak performance zfs likes to have the whole disk device. However partitions may give you flexibility at a little cost in speed. It might give you better options for switching filesystems types. Please note I suspect having both zfs and btrfs might cost you memory. virtualbox may also cost you a little network performance.

Anyway you can watch this from someone using zfs on their home server:-
- http://www.youtube.com/watch?v=hxOVgUTxniw

Neither of the two are desktop orientated, though both will do a desktop. Other distros may do the desktop better but be less well orientated at zfs / btrfs.

d) Any thoughts on the hardware ? Compatibility ? Any graphics card should work or is solaris very specific ? I have 2 Nvidia Quadro cards lying around as spares as well.

I suspect the latest bleeding edge cards may be a problem. And I have been upset with graphics cards in time past.

Will be grateful for your suggestions / expert advises !

Thanks

Please dont take my advice as definitive, rather than 'expert', and as just as a couple of ideals to think about. Different people will have different priories and come to different conclusions. Your kit certainly give you some options for virtual machines.

Neither of the two are desktop orientated, though both will do a desktop. Other distros may do the desktop better but be less well orientated at zfs / btrfs.

For Solaris 11 I've taken a "Chromebook" attitude towards the desktop. You can find an online version of just about anything so instead of hoping and praying for a native desktop app or searching for a Java based one, use a search engine and find an online version and use that. I actually looked over the Chrombook apps list and added several to my list of links for Solaris users.